Dental engine attachment



Feb. 4, 1947. H. FREEDMAN DENTAL ENGINE ATTACHMENT Filed June 'r, 1945INVENTOR Patented F ch. 4, 1947 DENTAL ENGINE ATTACHMENT Hyman Freedman,New York, N. Y., assignor of one-half to Bertha Freedman, New York, N.Y.

Application June 7, 1943, Serial No. 489,901

9 Claims.

This invention relates to improvements in dental engines and hasparticular reference to a supporting means forthe hand piece or dentaltool.

Heretofore, it has been the common practice to provide a supporting hookon the extension arm of a dental engine from which hook the hand pieceis suspended when not in use. In actual practice, a dentist, during anoperation, has many occasions to replace the hand piece in its suspendedposition on the hook and often does so Without observing whether thetool is secure thereon. As a consequence it is not uncommon for the toolto become accidentally detached and fall from its hook with considerableforce and strike a patient with the possibility of serious injury. Infact, only recently, an accident of this nature happened and a drillattached to the hand piece penetrated a patients skull, resulting in herdeath.

To minimize the possibility of such unfortunate accidents, it isproposed, by the present invention, to provide additional meanssupplementing the customary supporting hook which Will effectivelyprevent the fore arm that carries the hand piece from falling in theevent that said hand piece should become accidentally detached from saidhook while in a suspended position thereon.

Accordingly, a feature of the invention is to provide means associatedwith the extension and fore arms of the dental apparatus and preferablyarranged adjacent the pivotal connection between said arms, which meanswill become efiective to retain the fore arm in the position it assumeswhen the hand piece is suspended on the supporting hook should said handpiece become accidentally detached from said hook.

A further and more specific feature is to mount a permanent magnet onone arm of the apparatus in such manner that said magnet will remain inmagnetically opposed relation to another arm in respective of anyturning movement of the first named arm relative to said magnet.

The inventive idea involved is capable of receiving a variety ofmechanical expressions some of which, for purposes of illustration, areshown limits thereof, reference being had to the ap pended claims 1? orthis purpose.

In the drawing: Fig. 1 is a fragmentary elevational view of a dentalengine of conventional form, showing the present invention appliedthereto. Fig. 2 is an enlarged side elevation of the magnetic means forretaining the extension and fore arms in their inoperative positions.

Fig. 3 is a section on the line 33 of Fig. 2.

Fig. 4 is a section on the line 4-4 of Fig. 2.

Fig. 5 is a section on the line 5--5 of Fig. 2.

Fig. 6 is a view similar to Fig. 2, partly in section, showing amodified form of the invention, and

Fig. 7 is a section on the line '!-'I of Fig. 6.

Referring more particularly to the drawing, the numeral It indicates aportion of the engine arm of any conventional type of dental engine,which arm is provided at its outer end with the upper pulley H aroundwhich passes the usual drive belt A2 for the hand piece IS. Theextension arm E l has a universal pivotal connection at its upper endwith the arm IB and, at its lower end, has a similar connection with thelower end of the fore arm [5. An idler pulley I6 is also located at thelower ends of said arms and the belt I2 also engages around said pulleyand then extends upwardly and around the pulley I! at the upper end ofthe arm is, and from thence to the drive pulley IS on the hand piece [3.The upper end of the arm l5 has the usual universal connection with anarm 19 which carries said handpiece l3 and, when the latter is not inuse, it is engaged with a supporting hook 26 attached to the extensionarm M adjacent-its upper end. The construction thus far described iswell known in the art and therefore requires no further ex planation.

In accordance with the present invention, means are provided forreleasably retainingthe arm 15 in its suspended or inoperative positionshown in Fig. 1 in the event that the arm l9 should become accidentallydetached from the hook 2t, and thereby prevent said arm IE, togetherwith the hand piece i3, from falling away from said hook. Said means isdesirably positioned between and associated with the lower ends of thearms M and i5 and preferably takes the form of a permanent horse shoemagnet 2! supported on the arm l4 and a keeper 22 carried by the arm E5.As will be evident, said magnetic elements, when brought into proximity,will attract each other and the magnetic flux passing between the samewill be sufiicient to hold the arms 54 and i5 in their suspended orinoperative positions even though the arm I9 is disengaged from the hook29.

In order to support the magnet 25 on the arm 14 so that said magnet willremain in opposed relation to the keeper 22 regardless of any axialturning movement of said arm, a casing 23 is provided for said magnet,which casing is made of any suitable non-magnetic material such asbrass. Said casin comprises side walls 24 between which the magnet isreceived and wherein it is secured by a rivet 25. One end of said casingterminates in opposed resilient clamping portions 26 which areengageable about the sleeve 21 in which the arm I4 is rotatable. Saidsleeve extends upwardly from a rectangular member 28 upon which thelower ends of the clamping portions 25 rest and, in order to prevent anyrotation of the casing while the arm I4 might be rotating in saidsleeve, said clamping portions are provided with depending extensions 29which engage opposed faces of the stationary portion 28.

The support for the keeper 22 is somewhat similar in construction tothat of the magnet 21. Thus, as best shown in Fig. 5, said supportcomprises a member 36 having opposed clamping portions 3i whichpartially embrace a sleeve 32 carried by the upper end of a rectangularmember. 33, and extensions 34 on the lower ends of the clamping portions3i engage opposed faces of the member 33 so that said support will notturn if the arm 15 is rotated. The keeper 22 is resiliently carried bythe suport 30 by means of two coil springs 35 interposed between andsecured to said support and keeper, this construction enabling thekeeper to at all times haveflush en- I gagement with the pole pieces ofthe magnet 2!. Also, by providing a mounting of this character for thekeeper and having the springs 35 of proper tension, it will be observedthat as said keeper approaches the magnet toward the end of the movementof the fore arm to its inoperative position and before the hand piece isengaged with the hook 2d, the magnet will become effective to attractsaid keeper and thus hold said fore arm in said position even if thehand piece should not be engaged with the hook.

In such construction it will be noted that as the forearm I is movedtoward the extension arm It, the keeper 22 will move forward intoengagement with the permanent magnet 2| at an accelerated speed. Uponengagement of the kepeer with the permanent magnet an audible sound orsignal is heard which immediately indicates to the operator that themagnetic lock has been made effective. On the other hand, if theaforementioned arms, upon relative movement toward each other do notproduce an audible sound or signal the operator is warned of the failureof the securing means to become effective.

In the form of the invention shown in Figs. 6 and 7, the magnet 36 ismounted on a support 31 which is of substantially the same constructionas the member .23 and is carried on the sleeve 2! associated with thearm M. However, instead of providing a keeper on the arm l5, the sleeve38 in which said arm is rotatable is made of magnetic material and isdirectly engageable with the pole pieces 33 of the magnet 35 when thearms M and P5 are in their inoperative positions.

What is claimed is:

1. .In a dental engine, pivotally connected extension and-fore arms thelatter of which has v an infinite numer of inoperative positions, one ofsaid positions being adjacent said extension arm, members in which bothsaid arms are axially rotatable, magnetic elements supported by saidmembers in opposed relation to each other and disposed adjacent thepivotal connection between said arms, and means to retain said magneticelements in such relation irrespective of any rotary movement of eitherof said arms.

2. In a dental engine, pivotally connected extension and fore armshaving an infinite number of inoperative positions, said fore arm havingan inoperative position adjacent said extension arm, a member includinga sleeve, in which one of said arms is axially rotatable, a removablecasing positioned adjacent the pivotal connection between said arms andhaving clamping portions engageable with said sleeve said casing havingmeans engaging said member to prevent rotation of said casing when saidarm is rotated, and a magnet supported by said casing contiguous to saidpivotal connection and operatively associated with the other of saidarms to retain said fore arm in its inoperative position.

3. In a dental engine having a forearm, an extension arm, and means formounting a tool on said forearm, primary locking means for supportingsaid forearm in a first locked position, and secondary locking means forsupporting said forearm in a second locked position adjacent saidfirstposition, said secondary means including mechanism actuated bymovement of the forearm to a point proximate either of said lockedpositions.

4. In a dental engine having a forearm, an extension arm, and means formounting a hand tool on said forearm, primary means for supporting saidforearm in a first position, and secondary means for supporting saidforearm in a second position adjacent to and spaced from said firstposition, said secondary means comprisin a member mounted on one of saidarms, and a second member mounted on the other of said arms and actuatedto connect with said first member upon movement of said second member toa point proximate said first member and before said other arm hasreached said second position.

5. In a dental engine having a forearm, an extension arm, and means formounting a hand tool on said forearm, primary means for supporting saidforearm ina first position, and secondary means for supporting saidforearm in a second position adjacent said first position, saidsecondary means comprising a fixed member mounted on one of said armsand a movable member mounted on the other of said arms adapted toconnect with said fixed member upon movement of either of said memberstoward the other.

6. In a dental engine having aforearm, an extension arm and means formounting a tool on said forearm, primary means for supporting saidforearm in a first position, and secondary means for supporting saidforearm in a second position adjacent said first position, saidsecondary means, comprising a magnet fixedly mounted on one of said armsand a keeper bar resiliently mounted on the other of said arms, saidkeeper bar being actuated to connect with saidmagnet when one of saidarms is moved to a point proximate said first position.

7. In a dental engine having a forearm having an infinite number ofinoperative positions, an extension arm, and means for mounting a toolon said forearm, a first and second inoperative positions for saidforearm, said second inoperatve position being spaced from said firstinoperative position, means for retaining said forearm in said firstinoperative position, and means for retaining said forearm in saidsecond inoperative position, said last means becoming efiec- 5 tive assaid forearm moves from said first inoperative position to said secondinoperative position. as

8. In a dental engine having a forearm having an infinite number ofinoperative positions, an extension arm, and means for mountin a tool onsaid forearm, means pivotally connecting one end of each of said arms,said forearm having a first inoperative position and a secondinoperative position adjacent said first position and magnetic meansdisposed on at least one of said arms adjacent said pivotal connectionfor maintaining said forearm in said second position.

9. In a dental engine as described in claim 8, and means for supportingsaid forearm in its first inoperative position, said last meanscomprising a hook mounted on said extension arm. said hook beingengageable by said tool mounting means.

HYMAN FREEDMAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,198,227 Hinchey Sept. 12,19161,340,908 Pieper et a1 May 25, 1920 2,288,688 Dubilier July 7, 1942148,920 Bonwill Mar. 24, 1874 1,495,673 Cliffton May 27, 1924 1,037,134Cottle Aug. 27, 1912 1,038,752 Hofbauer Sept. 17, 1912 2,188,034 DarbyJan. 23, 19 10 2,286,740 Krause June 16. 1942

